The FIB machining observation apparatus is an apparatus which performs sample microfabrication by focusing an ion beam and irradiating it to a sample (Patent Literature 1 and 2). The ion irradiation to the sample permits sample sharpening through spattering. Through detection of a secondary electron simultaneously emitted from the sample, a scanning ion microscope (SIM) image can be obtained. That is, since sample machining and observation can be performed in parallel, it is suitable for performing microfabrication at a specified place of the sample. Thus, it is used for defect analysis of a semiconductor and fabrication of a thin sample and a needle-like sample for a transmission electron microscope. Further, in case of a multifunction apparatus (FIB-SEM) combining an focused-ion-beam machining observation apparatus and a scanning electron microscope (SEM), machining with an FIB and accurate observation based on the SEM image can be performed in parallel, making it possible to machine a sample with a fine structure which cannot be observed on the SIM image.